Mick
The clues given to Holmes were almost accurate , enough to know what meant Waltz as " first water " and " second water " . IMO , the Waltz's first water was/is the Agua Escondido and the second water was/is what we know today as First Water .
There also exist a mistake in the clues given to Holmes , and this maybe because Waltz used to give clues to " his " mine from two directions and at the time he gave the clues to Holmes , was somehow confused or partially in delirium . And this mistake , IMO , is how the point which you can see the man rock is not where the Gov trail turns south , but when the trail at the same point ends to the south . So , Waltz " saw " that point up side down . Also at this point , was located the Mexican camp which we can " find " in the German clues and other maps .
Now , another worth unwritten clue that you have to know , is how you can see the man rock only in the morning and late evening , because in the middle of the day , you will have the sun in your eyes .This means how you have to camp in the mountains to " catch " the moment .
Also , the stone maps , like the Red Hills clue , don't give a clue where the stone trail starts . The only clue on the stone maps is the Horse landmark . IMO , find the horse clue and you will find the other , including the stone trail .